Try changing the SMTP authentication options in Account settings or contact your network administrator. Unfortunately we also have never found a place to select 'StartTLS'. I have had my ISP tech here and check all settings but was unable to resolve. Account name: 'Esedona' I do not see where to change the SMTP authentication method to something it will accept. I have talked with Apple support but they say talk to Microsoft.

• Postfix For Mac

Postfix For Mac

I recently upgraded my Mac to use Apple’s latest operating system, Mountain Lion, and in so doing, wiped out my postfix configuration that I had previously set up with advice from many different blogs. Postfix is essential for my line of business where I send many emails through on my local machine. After hours of updating settings and getting nowhere, I stumbled across a that set me in the right direction. Rather than do this process again when Apple releases a new upgrade, I decided to document the steps I took to get this working (more for a reference for myself, but also to help those with the same issues). I personally use Google Apps, so this process is for those also trying to authenticate through Gmail. This process is much simpler if you don’t need SSL encryption when sending mail. I use as a text editor, so the following command line options use the ‘mate’ command.